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steve308
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| Posted: Mar 01 2026 at 6:23pm | IP Logged
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2012 175000 miles pro4x just set this code. P0171 What
order should I try to run the cause down.
Hose cracked or leaking
o2 sensor
Mass air flow sensor
Injector
Fuel filter.
Thanks in advance
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Rubble
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| Posted: Mar 02 2026 at 1:08am | IP Logged
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steve308 wrote:
2012 175000 miles pro4x just set this
code. P0171 What
order should I try to run the cause down.
Hose cracked or leaking
o2 sensor
Mass air flow sensor
Injector
Fuel filter.
Thanks in advance |
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1st Thing I would download the Genuine Nissan Service
Manual. Google for Free Download.
I would Look at The Air Filter & Replace if Too Old or Even
Look's Slightly Dirty. While you have the Air Filter Out Look At
The maf sensor and Clean with a maf sensor Cleaner and
Follow the directions to the letter so not to scratch or damage
the sensor. Be sure to put the Air Filter back in correctly and
make sure that the Top Cover is fitted on correctly and tight. I
have to help the 3 prong fittings into the hole's on one side, with
my finger's, otherwise the top cover won't fit snug and let air in
past the air filter. Make sure that somebody hasn't damaged
those fitting's; if they have then you may have to get a new air
filter box or you may be able to mend them with a plastic welder.
Check all the Air Intake Hose Clamp's to make sure eveything is
tight. 1st loosen just a tad then tighten, so not to get too tight.
Clear the code and see if it come's back. If it doesn't I would
call it a day. If it does then follow the diagnostic procedure's in
the Nissan Service Manual. If You are not able to do this
Yourself,, then I would take it to Nissan and See If they can
Figure out what the problem is.
The Fuel Filter is inside the Gas Tank and Part of The Fuel
Pump, so I would consider that as a last resort.
Might be the o2 sensor,, but you need to verify this with the
procedure's in the Nissan Service Manual.
Take your Time and use a Shop Light to help you see what you
are doing better. Lot's of time's a Small Shop Mirror can help
you to see underneath and other area's that are hard to see
very good.
It's best imo not to start throwing part's @ it in hope's something
will stick. Either go through the diagnostic's or take it to a
professional mechanic. My 1st choice would be Nissan. My
next choice might be Firestone if they have an Experienced
Mechanic.
Let us know how its going.
__________________
Barney ~ NOT A PROFESSIONAL MECHANIC ~ ALWAYS GO BY THE GENUINE NISSAN SERVICE MANUAL ~ 2013 SV V6 Frontier KC/AT/2WD Bought New ~ '93 I4 Hardbody KC/AT/2WD Bought New, Owned 20 yrs. Sold.
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steve308
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| Posted: Mar 02 2026 at 12:39pm | IP Logged
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Thanks for the prompt responce! I'll do the map sensor
cleaning as recommended. I'll have to wait a day or two as
it's now snowing and to cold to work outside.
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Rubble
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| Posted: Mar 02 2026 at 1:21pm | IP Logged
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steve308 wrote:
Thanks for the prompt responce! I'll do the
map sensor
cleaning as recommended. I'll have to wait a day or two as
it's now snowing and to cold to work outside.
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That's Right, Wait Till it's Warm Enough to work with your tool's
and Your Hand's and Finger's don't get too cold.
I hate to work with cold hand tool's. It just depresses me.
One thing that help's though when I have to work in the cold is
one of those round heater's that attach on top of a 5 or 10 gallon
propane tank. At Least I can warm my hand's up from time to
time useing it. I think I got mine from Harbor Freight, but
Lowe's, Home Depot, and Maybe even WalMart sell's them.
Sometime's I even take a shot of Whiskey To Warm The
Enerd's.. 
Anyway Best To wait till it's warm enough. Be sure to check all
those Connection's coming from the Air filter Box. Sometime's
they work loose or somebody may have forgotten to tighten one
correctly.
Good Luck
__________________
Barney ~ NOT A PROFESSIONAL MECHANIC ~ ALWAYS GO BY THE GENUINE NISSAN SERVICE MANUAL ~ 2013 SV V6 Frontier KC/AT/2WD Bought New ~ '93 I4 Hardbody KC/AT/2WD Bought New, Owned 20 yrs. Sold.
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steve308
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| Posted: Apr 03 2026 at 4:49pm | IP Logged
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Thought I would follow up. I changed the air filter
although it was not that old, and cleaned the map sensor as
was suggested and cleared the code. I've put about 100
miles on the truck and so far, the light has not returned.
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Rubble
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| Posted: Apr 04 2026 at 7:13am | IP Logged
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steve308 wrote:
Thought I would follow up. I changed the
air filter
although it was not that old, and cleaned the map sensor as
was suggested and cleared the code. I've put about 100
miles on the truck and so far, the light has not returned.
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Hey Steve,
Let's Hope that was the problem.
I Really Hate all these Electronics that We have to Deal With
Now. We are haveing to deal with more electronics on Even
Tractor's Now that they've added an ECM, Exhaust Monitoring,
etc.
Be sure to download the Genuine Nissan Service Manual for
problem's in the Future. The Genuine Nissan Service Manual
has instruction's that used to be in The Owner's Manual on How
To: Change the ATF, Coolant, Rear Axle Houseing Oil, Cabin Air
Filter's, etc. On My 2013 There is a Procedure to Change out
the Coolant that Most Don't Follow Correctly and wind up with
Trapped Air in the System. I've seen Post's Online that There
is No Special Procedure for Changeing Out The Coolant ~ But
Those Folk's Haven't Followed The Nissan Service Manual
Instructions.
Not in Any Manual That I've Seen Anywhere But: Every Year or
So ~ Remove The Rear Axle Breather ~ Clean It Out with
something ( I Run Some Diesel Fuel Through Mine) ~ Blow It
Out With Compressed Air. The Breather Can Get Stopped Up
With Dirt, Mud, Frozen Junk, etc. If the Breather Get's Stopped
Up, Pressure Can Build Up in The Axle Houseing and Cause
The Axle Seal's To Start Leaking. Mine only hold's about 1 1/2
Qt's, So It Doesn't Take much Leakage to Get Too Low For
Lubrication and Then Whammo ~ Big Expense..
Lot's Of Good Info on the WWW, but There is Also Lot's Of Bad
Info On The WWW. Alway's Follow The Genuine Nissan
Service Manual is my Advice.
Thanks for letting us know how it is going.
__________________
Barney ~ NOT A PROFESSIONAL MECHANIC ~ ALWAYS GO BY THE GENUINE NISSAN SERVICE MANUAL ~ 2013 SV V6 Frontier KC/AT/2WD Bought New ~ '93 I4 Hardbody KC/AT/2WD Bought New, Owned 20 yrs. Sold.
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Nissan Frontier Forums : Problems / Technical
Topic: Code P0171
